It is well known for smart cards (both conventional smart cards with contacts, and inductively powered contactless smart cards) to contain information identifying a bearer and to allow access to a user asset. Security passes are a further example of a technology in which inductively powered devices are used to identify a bearer—for conventional security pass technology, the presence of a valid security pass is sufficient to operate the security mechanism.
For a number of applications, existing technologies such are these are unsatisfactory. They may be relatively insecure—in the case of a conventional security pass, simply obtaining the security pass may be enough to enable access for an unauthorised person. Many techniques for physical attack upon smart cards are known, and smart cards are also an unsatisfactory form factor for many applications—such as a passport, or a bank passbook. In such cases a known approach is to provide a physical book and a separate smart card—however, it would clearly be desirable to provide instead a physical document that provides a satisfactory measure of security, while preserving the possibility of providing various significant information digitally, as is possible with a smart card.